IO80 Appendix VI. I2, the value of which is required. The distance apart of these axes is #, so by Euclid II. 13 And I2 = 2 m-f* = 2 But, having regard to sign, % m-d = zero, Also, S*«-£2 = I-L And, S?//-#2 = whole area x #- .*. 1 2 = Ij -f (area x #'2) We may now find the 2nd moment of any beam section that CAST //?o/v of Rje£jusJjcuvc&. Jfyq. 957. can be cut up into a number of regular figures whose 2nd mo- ments are obtainable by well-known formulae, the total value being the addition of the moments of the parts round the neutral axis. Two examples have been given in Fig. 957. Taking the cast-iron beam, the neutral axis is found by moments round H, as at top of p. 432. 12 X O = O 7i x 4$ = 33*5 IF x 3i = 4'24 3l x 8i = 3°*6 Total moments = 68-34 Total area J* 24!